Icon modification

Example using a Modify interaction to edit an icon.

The icon on this map can be dragged to modify its location.

The Modify interaction can be configured with a hitDetection option. With this option, the modification candidate will not be determined by the pixelTolerance, but match the visual appearance of the geometry.

main.js

import Feature from 'ol/Feature.js';
import Map from 'ol/Map.js';
import Point from 'ol/geom/Point.js';
import View from 'ol/View.js';
import {Icon, Style} from 'ol/style.js';
import {Modify} from 'ol/interaction.js';
import {OGCMapTile, Vector as VectorSource} from 'ol/source.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';

const iconFeature = new Feature({
  geometry: new Point([0, 0]),
  name: 'Null Island',
  population: 4000,
  rainfall: 500,
});

const iconStyle = new Style({
  image: new Icon({
    anchor: [0.5, 46],
    anchorXUnits: 'fraction',
    anchorYUnits: 'pixels',
    src: 'data/icon.png',
  }),
});

iconFeature.setStyle(iconStyle);

const vectorSource = new VectorSource({
  features: [iconFeature],
});

const vectorLayer = new VectorLayer({
  source: vectorSource,
});

const rasterLayer = new TileLayer({
  source: new OGCMapTile({
    url: 'https://maps.gnosis.earth/ogcapi/collections/NaturalEarth:raster:HYP_HR_SR_OB_DR/map/tiles/WebMercatorQuad',
    crossOrigin: '',
  }),
});

const target = document.getElementById('map');
const map = new Map({
  layers: [rasterLayer, vectorLayer],
  target: target,
  view: new View({
    center: [0, 0],
    zoom: 3,
  }),
});

const modify = new Modify({
  hitDetection: vectorLayer,
  source: vectorSource,
});
modify.on(['modifystart', 'modifyend'], function (evt) {
  target.style.cursor = evt.type === 'modifystart' ? 'grabbing' : 'pointer';
});
const overlaySource = modify.getOverlay().getSource();
overlaySource.on(['addfeature', 'removefeature'], function (evt) {
  target.style.cursor = evt.type === 'addfeature' ? 'pointer' : '';
});

map.addInteraction(modify);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Icon modification</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "modify-icon",
  "dependencies": {
    "ol": "9.1.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}